Submerged arc welding with granular flux is a common commercial welding technique. In this technique granular flux is spread in a mound in front of a welding head as the welding head moves across the area of the workpiece being welded. The purpose of the flux is to prevent the welding arc from being exposed to the atmosphere. The electrode in the welding head runs through the flux and the welding arc is fully submerged in the mound of flux. To hold the flux in place while the electrode is passing through the mound, a flux dam is used. A flux dam also aids in forming the mound, reduces the amount of flux required to submerge the welding head and prevents flux from being wasted.
Since a flux dam is positioned adjacent to the welding head, the dam is subjected to high heat from the arc. Typically flux dams overheat, rapidly deteriorate, and burn up in a short period of time. In addition, when the dam begins to deteriorate, its surface becomes irregular and its shape distorts. Flux then can bleed out underneath the dam causing flux to be wasted and possibly leading to exposure of the arc to the atmosphere.
There have been several solutions suggested to the problem of deterioration of flux dams. One technique is the use of a stationary dam that is physically attached to the workpiece. This type of dam rapidly deteriorates and is usually not reused. A second solution has been the use of a traveling dam. A traveling dam moves with the welding head and is water cooled.
Prior patents in this area of technology include U.S. Pat. No. 2,808,500 to Pandjiris issued October 1, 1957; U.S. Pat. No. 2,900,487 to Danhier issued Aug. 18, 1959; and U.S. Pat. No. 2,972,042 to Ashbaker issued Feb. 14, 1961.
Prior solutions to the problem of dam deterioration have never proven to be totally satisfactory. In production situations these dams still deteriorate too rapidly. This requires that the welding process be stopped, the apparatus be disassembled, and the dams replaced.
A further problem is the long setup time required. In production situations the flux dam and the welding head must constantly be positioned on new workpieces and then moved out of the way when the weld is completed. It is desirable to speed up the positioning of the flux dams as much as possible but heretofore flux dams have slowed production because they are awkward to move and must be constantly adjusted.
The present invention is directed to overcoming one or more of the problems as set forth above.